Currently, disposable razors provide a substantial portion of the market for wet shaving.
With the exception of the blade or blades (and possibly a spacer) the disposable razors are made out of thermoplastic material. The various components, depending upon the ultimate design are molded separately and then assembled. For example, the "MicroTrac" disposable razor manufactured by Gillette molds a single unit blade seat, back and cap with the cap being in the form of fingers. The blade subassembly consisting of two blades and a spacer is inserted between the molded cap and seat with the finger-like projections extending from the top of the cap serving as leaf springs to retain the blade subassembly by a friction fit. This combination is then mated to a handle by press fitting a tab-finger combination. It is apparent that this process involves not only separate steps but separate work stations requiring individual subassembly and ultimately assembly.
Other assembly processes for disposable razors utilize staking from projections depending either from the cap or the seat which mate with reciprocal openings in the other part and position the blades and/or spacer. The handle is usually mated separately to the seat portion. Again, separate assembly steps at different locations is required to produce the disposable razor.
Ultimately, a disposable razor which could be assembled at a single work station having all of the plastic parts produced in a single cavity would be desirable because the steps of subassembly, final assembly and the conveying of the various components from location to location around the manufacturing area could be eliminated.
U.S. patent application Ser. No. 615,603 filed in the name of Ernest F. Krialy et al. on May 31, 1984 describes a razor with a blade having a slot therein. According to the application, the blade is permanently secured in the head portion of the razor and the handle and guard bar portion are molded integrally with the head.
British Pat. No. 1,565,296 cited during the prosecution of the above referred to application discloses making a unitary handle, guard member and blade support and then attaching a Z-shaped blade by upset rivots or the like.
U.S. Pat. No. 4,489,627 issued Dec. 25, 1984 to Lembke describes a razor manufacturing process in which a double edge strip of blade metal is parted along a center line and cropped to form two strips each containing a series of spaced apart blades connected by webs to an elongate backing strip. Each strip, which now consists of a plurality of blades and a backing strip, is fed into a molding machine in which, either the shaving unit or blade containing component of a razor, is molded directly around each individual blade. The web is then parted to release the molded razor, etc. from the backing strip. It is unclear according to the teachings of Lembke how the remaining razor components are manufactured if they are not made in a "single shot" by molding. It is apparent, however, that the molding machine completely surrounds the blade segment during molding. Lembke therefore requires the handling of an elongated strip metal, its control and insertion in either a multi cavity mold or a very large single cavity mold and the production of either a series of razors or heads joined together in a single unit which must be subsequently disassembled. Conveying of a metal web of the type described is extremely difficult when it is necessary to protect a delicate cutting edge and even more so when two cutting edges must be protected.